Stress aid designed for accidents (9)
I believe the answer is:
disasters
'accidents' is the definition.
(disaster is a kind of accident)
'stress aid designed' is the wordplay.
'designed' indicates an anagram (designed with the letters).
'stress'+'aid'='stressaid'
'stressaid' is an anagram of 'DISASTERS'.
'for' acts as a link.
(Other definitions for disasters that I've seen before include "Events resulting in great loss and misfortune" , "flops" , "accidents?" .)